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High Idle w/ Hard Shifting! Whats happened?!


99div-ill

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:huh: I Don't know whats happened. But I am new here, and hope someone can help me out.

This is a 99 Deville Concourse with a Northstar. 78k miles.

Story / Problem :

I was driving home from work, this is about 15 miles. Driving as normal, car seemed to want to 'take off', the accelerator was very sensitive. I was trying to be as smooth as I could until I got it home. Now @ home the car would idle fine in drive but as soon as I shifted it to park it was very hard/heavy shifting. You could hear and feel the car shift where normaly its smooth. Now the car is in park and is idling very high, between 1900-2100 rpm, and as i tap the gas the idle would go higher and very slowly move back to to 1900-2100 rpm. Shifting back into ® or (D) was very hard/heavy hitting and (N) would idle just as high as (P)?!?! -_-

I have heard something about cleaning my TB (throttle body) and doing a 'Relearn' on P014 and P015 which I have never heard of... nor do I know how to do it. Can someone please help me I still have to drive the car to get to work tomorow and don't want to blow up! :o

Thank you in advance - whoever may know my trouble.

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:welcomesmiley: The first thing I would do is get the OBD trouble codes and post them here. Here's how:

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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:welcomesmiley: The first thing I would do is get the OBD trouble codes and post them here. Here's how:

</a>

Maybe you could help me once more, there is nothing about a 99 Concorse on there or maybe I am overreading it with all those abbrev. ? How is it I find the codes for a 99 Deville Concorse? (the 99 'deville' exam. they give includes a 'warmer/red' button, which i do not have, just a knob to adjust temp.)

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:welcomesmiley: The first thing I would do is get the OBD trouble codes and post them here. Here's how:

</a>

Maybe you could help me once more, there is nothing about a 99 Concorse on there or maybe I am overreading it with all those abbrev. ? How is it I find the codes for a 99 Deville Concorse? (the 99 'deville' exam. they give includes a 'warmer/red' button, which i do not have, just a knob to adjust temp.)

The Concours should be similar to the STS - Simultaneously press and hold the OFF and PASSENGER WARMER buttons until the display goes into the segment check. Have a pen and paper ready to record any codes that appear on the information center.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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OK that worked! now how do I understand/navigate this??? I kept saying "No 'xxx' Codes" (like pci, msm, isa, ect.)?? and "BCM#### History" and back to more "No 'xxx' Codes", at the VERY end it just stopped at PCM? until I hit the info reset and everything went back to normal.

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They all say 'No xxx Codes'

such as,

No PCM Codes

No MSM Codes

No MMM Codes

No DIM Codes

ect.

but they ALL say NO... then at the very end it says " PCM? " and if i hit the off button again it just reruns the whole 'test' saying the same thing.

do you need to know all the PCM,MSM,MMM, ect's? would that help? should they all say NO ?? :huh:

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The first place to start is the throttle body clean it with O2 safe carb cleaners or GM upper engine cleaner and a tooth or detail brush. Be sure you clean the rear of the throttle plate and the throat of the throttle body where the plate meets the throat. This happens to my car once in a while also. Since you have no codes (which is surprising) I would start there.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Now I start it again and everything is "fine". But what is really giong on??? Has anyone had this before??? <_<

OH yea.......It happens to me 2 or 3 times a year on my 98 Deville only when it extremly humid ond extremly hot outside.I shut the car off and restart it again until it goes away.Only 2 or 3 times a year I can live with so I have done nothing about it....

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They all say 'No xxx Codes'

such as,

No PCM Codes

No MSM Codes

No MMM Codes

No DIM Codes

ect.

but they ALL say NO... then at the very end it says " PCM? " and if i hit the off button again it just reruns the whole 'test' saying the same thing.

do you need to know all the PCM,MSM,MMM, ect's? would that help? should they all say NO ?? :huh:

The PCM? means the system is waiting for input. The fan up/dn button is used to input nes/no. To exit diagnostics, push the AUTO button (or press the temperature control).

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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They all say 'No xxx Codes'

such as,

No PCM Codes

No MSM Codes

No MMM Codes

No DIM Codes

ect.

but they ALL say NO... then at the very end it says " PCM? " and if i hit the off button again it just reruns the whole 'test' saying the same thing.

do you need to know all the PCM,MSM,MMM, ect's? would that help? should they all say NO ?? :huh:

Apparently you don't have any trouble codes from the OBD system. The key is "NO PCM CODES." If the computer saw something wrong with a sensor or idle control or whatever, there would be at least one code. This is important too because there are only a few things that the computer doesn't see, and just about the only things that would cause high idle speed are a sticking throttle cable or something hitting the throttle plate, like a whole lot of dirt in the throttle body. I would look for anything that might be amiss on the outside of the throttle body, too, like something caught in the throttle lever, a broken throttle return spring, a kink in the throttle cable, etc. Also look at your gas pedal...

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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You keep talking about the 're-learn', just disconnect the negative battery cable and drive the car, it will relearn. Fix it for good?, that is an over simplification. As your throttle body gets dirty, it compensates for the loss of air via the IAC. When you clean your throttle body you now allow more air, and you must kind of 're-initialize' or re-boot your PCM so that it resets its defaults.

If you don't do a relearn, the system will do it on its own also. Clean the throttle body good, it is NOT and easy job to do right, it will take about 30 minutes, as the carbon is hard to get off the rear of the plate. DO NOT get solvent into the TB, you can hydrolock the engine. Use rags, tooth brushes, detail brushes and GM UEC.

As Jim mentioned check the operation of the manual cables to make sure they are not binding also.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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You keep talking about the 're-learn', just disconnect the negative battery cable and drive the car, it will relearn.

To clarify - Disconnect the negative battery cable for 30 seconds and then reconnect it. Do not disconnect the cable with the engine running or the alternator will be damaged.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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You keep talking about the 're-learn', just disconnect the negative battery cable and drive the car, it will relearn.

To clarify - Disconnect the negative battery cable for 30 seconds and then reconnect it. Do not disconnect the cable with the engine running or the alternator will be damaged.

Good pick up, I was not clear, but for a reason. You can see I am tweaked by my statement "You keep talking about the 're-learn'"

But, I was kind of TWEAKED by this statement "I have seen alot of people in other forums talk about doing a "ReLearn", should I do this aswell??" and "Have you done a relearn ? I heard this may help me fix it for good" and that caused my poorly detailed response.

I came close to saying, see what the people on the other forums think. This guy is in a big rush, wanted to fix it last night, was looking for a quick fix, and bumped his thread. While I realize we are all in a hurry, proper non grating behavior gets better results, especially when many of us stepped up to help.

This is not personal, 99 div-ill, its just that your have a bull in a china shop style and its in bad taste to use info found on OTHER sites. Ask what you want HERE and we will help you HERE. If a re-learn was that important, you can bet we would have mentioned it, its an insignificant issue from 96 on if you ask me.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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could the problem be a sticking ISC motor? - I don't believe that will set a code either. & I'm not sure how to check if it's working either :(

No ISC motor on a 99, only 95 backward

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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